The present invention refers to sealed threaded joints for tubing pipes which can be used for joining of the string elements, used at oil and gas wells exploitation, used for transportation of liquid and gaseous substances, as well as for overhaul and tripping operation.
The tubing in oil and gas wells is exploited in adverse conditions, in corrosive media and under huge mechanical loads. Therefore, the general requirements for such tubing pipes includes high corrosion resistance, wear resistance, preservation of tightness at high loads, as well as high strength to provide passing ability in wells, especially in curved areas.
Currently in the state of the art there is a known sealed threaded joint for tubing pipes, which consists of male and female elements, the ends of which, both externally and internally, are produced with corresponding tapered trapezoidal threads, and that contact each other's tapered sealing and bearing end surfaces to create an internal sealing unit (RU 74661 UI, E21B 17/042. 10.07.2008).
The state of the art joint has the following shortcoming: loosening of the joint at a high combined mechanical load (e.g., in applications involving tension and bending).
The shortcomings of the current art are solved by the claimed invention by developing a sealed threaded joint for tubing pipes that can be applied for joining of gas and oil well string elements, operated at high loads.